I use the personalized preview a lot and like it so far.
The following are ideas to improve it even more:

Exclude books...

• I did not rate / review at all from the recommendation
• I rated poorly (e.g. below 2.5 stars)
• I have on my TBR

We already have the survey for recommendations, which I like and use. It would be nice if it was used for the personalized preview as well.

For context, I added all my child and teenager reads to StoryGraph, but without review or rating.
E.g. the whole Harry Potter is something I would most likely not enjoy as much today as I did twenty years ago, but I don't want to rate it poorly to exclude it from the preview or recommendation.
But more often than not I see it as a reference for books I might enjoy, which is most likely not true.

The same goes for books I read recently, but did not enjoy as much and rated e.g. 2 stars. That's not a good reference point to me for a preview recommendation when I also read books of the same genre which I rated 4 stars or better in a similar time frame.
But those books also appear in the personalized preview.

And lastly I use my to read pile also as a point of reference for me to not forget about certain unpopular books. Those do interest me, fair enough, but I did not read them, so I think they might be a weak reference for the recommendation in the preview at best.